JohnKSa: I'm afraid you do have to worry about it, whether you own an actual firearm or not.

The short version is the BATF gets to determine what constitutes a silencer, and the way the way it's written now just about anything can be crammed into that category.

I have first hand experience with this and while it is questionable that I would have suffered any legal consequence, the business owner I was working with most certainly could have.

He wasn't in the gun business either, unless you consider paintball markers "guns". We manufactured aftermarket barrels for various paintball markers and some versions had what from a visual standpoint looked very muck like a silencer.

Removed from the barrel it was a piece of PVC pipe, two rubber o-rings, two delrin disks that pressed around the barrel, and a piece of furnace filter foam. Keep in mind the barrel itself was drilled full of holes and was itself an integral part of this system and when everything else was removed they were just a handful of plastic and rubber. The purpose of this stuff was to absorb the CO2 cloud when CO2 was the dominant power source before compressed air took off.

The fact that this stuff was just so much junk unless pressed on a barrel that was about .800 in diameter and punched full of holes made no difference to the two BATF agents that showed up, in person, to investigate. After all, you could just hack saw the barrel, slip it over a .22, and duct tape it in place. It only has to work once, and it only has to be 1db, and you've got yourself a silencer.

When the official paperwork came in it was cease and desist immediately. Failure to comply meant probable jail time and severe fines.

This isn't rumor or I had a friend that knew some guys brother. I was there. I even have a copy of the ruling floating around somewhere within all my household junk, though I doubt I could find it on purpose.

Bottom line is THEY get decide, not you or me, and the way it's written they can squeeze almost anything into that category if they feel they need to.

You don't have to take my word. Do a google search on BOA Barrels, The Concealer, and the BATF. I'm sure the story will pop up somewhere.